New Waste Exemption Regime for Anaerobic Digestion

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18 August 2010

There are four small scale waste permitting exemptions which may be relevant to AD Plant Operators.  Following a lengthy review by Defra, a new regime came into force on 6 April 2010 which has made minor changes to the existing exemptions.  This article concerns the two updated exemptions for on farm AD plant and digestate spreading which are summarised below:

On Farm AD Plant

In order to take advantage of the on farm plant exemption, there are certain requirements and limits that will need to be complied with.  In essence, Operators will need to ensure that:

  • They do not treat/store in excess of 1,250 m³ of waste at any one time (NB storage of manure/slurry waste from other farms will be included in this limit);
  • The waste remains in the plant for a minimum of 28 days;
  • The biogas produced is used to produce energy; and
  • The net rated thermal input is less than 0.4MW

Eligibility for the exemption will be lost if operators dispose of biogas by flaring or venting it into the atmosphere or if they attempt to compost manure and/or plant tissues.  For full Environment Agency guidance click here.

On Farm Digestate Spreading

Farmers need to be aware of and comply with the limitations that apply to the spreading of digestate if they wish to avail themselves of the on farm spreading exemption.  Importantly, farmers need to be aware that although the regulations establish quantitative limits on spreading which should not be exceeded, they are only entitled to spread an amount of digestate that is reasonably necessary to benefit the soil.  This quantity may be less than the amounts prescribed in the regulations.  Farmers availing themselves of this exemption will need to keep records of the quantity, nature and origin of all digestate spread for two years, unless they are already required to keep records under the nitrate regulations.

Full details of the various restrictions and limits can be accessed through Environment Agency guidance here

Registering the Exemption(s)

If you want to take advantage of any of the AD exemptions, you need to register the exemption(s) with the Environment Agency.  If your current AD operations are registered exempt under the old regime then you have until 1 October 2011 (if not longer depending on the operations) to transfer to the new regime.  If you carry out AD operations or spread digestate and do not fall within the terms of any of the exemptions, you will need to apply for an environmental permit.

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